Third order nonlinear optical susceptibility of films of polydiacetylene-containing polyamides and polyesters

Summary The third order nonlinear optical susceptibilities of cast films of diacetylene-containing polyamides, copolyamides and polyesters, were measured using degenerate four-wave mixing with picosecond pulses at 532 nm. The blue films of polyamides which contain aromatic polydiacetylene had ⁽³⁾ values of the order of 10^-9–10^-10 esu, while the orange films of polyesters having aliphatic polydiacetylenes showed ⁽³⁾ values of the order of 10^-10–10^-11 esu.     

A novel distance measure on q-rung picture fuzzy sets and its application to decision making and classification problems

Artificial Intelligence Review - In recent years, different higher order fuzzy sets have been introduced to better handle the uncertainty in many practical decision making and data mining problems....     

Vanadium Oxide Thin Films Alloyed with Ti, Zr, Nb, and Mo for Uncooled Infrared Imaging Applications

Microbolometer-grade vanadium oxide (VO _x ) thin films with 1.3 < x < 2.0 were prepared by pulsed direct-current (DC) sputtering using substrate bias in a controlled oxygen and argon environment. These films were systematically alloyed with Ti, Nb, Mo, and Zr using a second gun and radiofrequency (RF) reactive co-sputtering to probe the effects of the transition metals on the film charge transport characteristics. The results reveal that the temperature coefficient of resistance (TCR) and resistivity are unexpectedly similar for alloyed and unalloyed films up to alloy compositions in the ～20 at.% range. Analysis of the film structures for the case of the 17% Nb-alloyed film by glancing-angle x-ray diffraction and transmission electron microscopy shows that the microstructure remains even with the addition of high concentrations of alloy metal, demonstrating the robust character of the VO _x films to maintain favorable electrical transport properties for bolometer applications. Postdeposition thermal annealing of the alloyed VO _x films further reveals improvement of electrical properties compared with unalloyed films, indicating a direction for further improvements in the materials.     

OPTIMIZATION OF THE ELECTRON IRRADIATION IN THE PRODUCTION OF MoTe2 NANOTUBES

In this paper, we report the study of the production of MoTe₂ (molybdenum ditelluride) samples after a high dose of electron irradition. A 2 MeV Van de Graaff accelerator was used to irradiate the sample at the following conditions: 1.3 MeV voltage, 5 μA current, 25 kGy/min dose rate, and 1000 kGy total dosage. These conditions are maintain fixed while the irradiation dosages were changed to 50, 100, 200, and 500 Mrad. The optimization of the dosage used for the production of MoTe₂ nanotubes was obtained from the analysis of the samples that were examined in a high-resolution transmission electron microscope. The most efficient production of MoTe₂ nanotubes was obtained at the range between 100 and 200 Mrad. A very typical characteristic was obtained for rotated structures with angles of 4, 5, 7, 8, and 12° observed in the diffraction pattern for MoTe₂.     

Cochannel interference computation and asymptotic performanceanalysis in TDMA/FDMA systems with interference adaptive dynamic channelallocation

It has been shown through simulation results that the interference adaptive dynamic channel allocation (IA-DCA) scheme is a promising resource allocation strategy in time/frequency-division multiple-access (TDMA/FDMA) communication systems. The major obstacle in analyzing IA-DCA is the computation of cochannel interference without the constraint of conventional channel reuse factors. To overcome this difficulty, one needs a computationally efficient representation which can approximate the interference distribution accurately. For this purpose, a concept called channel reuse zone (CRZ) is introduced. Based on this new concept, both downlink and uplink cochannel interference are computed with two different propagation models, namely, a simplified deterministic model and a shadowing model. The results are then used to calculate the outage probability of the idealized, interference adaptive maximum parking (IAMP) scheme. Finally, as a significant contribution, an asymptotic performance bound for the two-way IA-DCA strategy is derived     

A neutronic investigation on a helium cooled hybrid reactor using nitride fuels containing reactor grade plutonium

There has been a significant amount of reactor grade (RG) plutonium accumulated from the conventional nuclear reactors’ spent fuel. Destruction or reducing this RG plutonium is very important to prevent its misuse and/or release accidentally into the environment. Using very energetic fusion neutrons in fusion–fission (hybrid) reactors can burn the RG plutonium effectively. This study presents the burning of the mixed fuel containing RG plutonium and uranium in a helium cooled hybrid reactor for an operation period of 24 months. Effect of various fuel mixtures and tritium breeders on the neutronic performance of the reactor as well as the burning of the RG plutonium was investigated. Calculations were carried out on an experimental hybrid blanket with the aid of SCALE4.3 by solving the Boltzmann transport equation with the XSDRNPM code. Numerical results showed that increasing RG plutonium content in the fuel increased the burning of plutonium and fusion energy multiplication substantially. The tritium breeder having the lowest lithium atomic density allowed the highest fission of the fuel in the blanket.     

Scalability of strained-Si nMOSFETs down to 25 nm gate length

Strained-Si nMOSFETs with a standard polysilicon gate process were fabricated down to 25 nm gate length with well-behaved characteristics and small difference in short channel effects. The performance enhancement degrades linearly as the gate length becomes shorter, due to not only the parasitic resistance but also heavy halo implant. Thus the key integration issues are how to manage threshold difference and As diffusion without excess doping. With comparable doping and well controlled parasitic resistance, up to 45% improvement in drive current is predicted for sub-50 nm gate length strained-Si nMOSFETs on the Si/sub 0.8/Ge/sub 0.2/ substrate. In this work approximately 45% enhancement is in fact demonstrated for 35 nm gate length devices, through advanced channel engineering and implementation of metal gates.     

Handover and channel assignment in mobile cellular networks

A taxonomy of channel assignment strategies is provided, and the complexity in each cellular component is discussed. Various handover scenarios and the roles of the base station and the mobile switching center are considered. Prioritization schemes are discussed, and the required intelligence distribution among the network components is defined     

A variational method in design optimization and sensitivity analysis for aerodynamic applications

Variational method is applied to the state equations in order to derive the costate equations and their boundary conditions. Thereafter, the analyses of the eigenvalues of the state and costate equations are performed. It is shown that the eigenvalues of the Jacobean matrices of the state and the transposed Jacobean matrices of the costate equations are analytically and numerically the same. Based on the eigenvalue analysis, the costate equations with their boundary conditions are numerically integrated. Numerical results of the eigenvalues problems of the state and costate equations and of a maximization problem are finally presented.